If the clips you'll be working with won't live on your system long, a stripe set (RAID 0) would be enough and would make renders faster, particularly if you're going to work with HD. I'm used to working with clips with a shelf life, so I like the added reliability of RAID 5 arrays.
10K=10,000 rpm hard drive; SSD= solid-state drive. Both are faster than a stock 7200 rpm hard drive that comes with most systems, but both are also more expensive than a 7200 rpm hard drive.
An internal Blu-ray Disc burner is generally a better choice, though technically I believe either USB 2.0 or FireWire should have enough bandwidth available to reliably burn a disc as fast as possible. Blu-ray Disc burners are pretty much a commodity item--there's not a lot that separates the different models; though there are some that do not handle CDs. I think Pioneer was the only company that put these kinds of drives out, though, and they are likely rare now. If LightScribe/LabelFlash are needed, keep your eyes out for that on spec sheets; that's about the only thing I can think of that might separate the drives that are out there. Quality-wise I would expect them to all be pretty close, but do check out some enthusiast sites (e.g. CDFreaks) if you have any lingering questions in that vein.
